I think it went off prematurely, too. I'd bet the perp was thinking of disguising the sound of the explosion behind the sounds of the booming "cannons" that the OU pep guys, the Ruf-Neks, fire off. They are thunderous.
They shoot them after touchdowns, but also right before half-time, when the Sooner Schooner is running off the field. There wouldn't be any way to predict when we might score a touchdown (at least, NOT THESE DAYS--any other season, it would just be whenever we had the ball, hee hee), so the most predictable "booming" would be happening right before half-time, or shortly AFTER this explosion happened.
With so many people, the crowd noise, and the sounds coinciding, or happening in conjunction with, the "expected" booming sounds on-field, it would perhaps be mass confusion to point to which direction the "real" bomb sound came from.
I watched a replay of the game on TV, and those cannons were really loud. On the other hand, I was listening closely through the last 10 minutes of the half, and didn't hear ANYTHING that sounded like an explosion.
Has anybody else listened to the replay of the game and pinpointed the sound of the explosion on the broadcast?